removed extra_sign_in_text examples for gitlab.rb [ci skip]

doc/customization/welcome_message.md

@@ -8,31 +8,5 @@ It is possible to add a markdown-formatted welcome message to your GitLab
 sign-in page. Users of GitLab Enterprise Edition should use the [branded login
 page feature](/ee/customization/branded_login_page.html) instead.
 
-## Omnibus-gitlab example
-
-In `/etc/gitlab/gitlab.rb`:
+The welcome message (extra_sign_in_text) can now be set/changed in the Admin UI.  
+Admin area > Settings
\ No newline at end of file
-
-```ruby
-gitlab_rails['extra_sign_in_text'] = <<'EOS'
-# ACME GitLab
-Welcome to the [ACME](http://www.example.com) GitLab server!
-EOS
-```
-
-Run `sudo gitlab-ctl reconfigure` for changes to take effect.
-
-## Installation from source
-
-In `/home/git/gitlab/config/gitlab.yml`:
-
-```yaml
-# snip
-production:
-  # snip
-  extra:
-    sign_in_text: |
-      # ACME GitLab
-      Welcome to the [ACME](http://www.example.com) GitLab server!
-```      
-
-Run `sudo service gitlab reload` for the change to take effect.